Apparatus for supplying fuel to internal combustion engines



, 1966 F. M. EVANS 3,292,546

APPARATUS FOR SUPPLYING FUEL TO INTERNAL COMBUSTION ENGINES Filed Feb. 8, 1965 2 Sheets-Sheet 1 Dec. 20, 1966 F. M. EVANS 3,292,546

APPARATUS FOR SUPPLYING FUEL TO INTERNAL COMBUSTION ENGINES Filed Feb. 8, 1965 2 Sheets-Sheet 2 United States Patent G 3 232,546 APPARATUS FOR SUlPLYING FUEL T INTER- NAL CONIBUSTION ENGINES Fraser Mackie Evans, Uxbridge, England, assignor t0 C.A.V. Limited, London, England Filed Feb. 8, 1365, Ser. No. 431,140 Claims priority, application Great Britain, Feb. 11, 1964, 40,149/ 64 4 Claims. (Cl. 103-2) This invention relates to liquid fuel pumping apparatus for supplying fuel to an internal combustion engine and of the kind comprising in combination, an injection pump, a body, a distributor movable in the body in synchronism with an engine with which the apparatus is associated to control the admission of fuel to the injection pump from a source of fuel under pressure alternately with the discharge of fuel from the injection pump to the engine and a metering valve for controlling the rate of flow of fuel from said source.

The object of this invention is to provide such a pump in a simple and convenient form.

According to the invention apparatus of the kind specified comprises a stepped cylindrical chamber defined in the body, and a complementarily stepped or equivalent shuttle in the chamber, the smaller end of the chamber being in communication with said source at a point upstream of the metering valve, and the wider part of the chamber being arranged to be connected through the distributor alternately with the downstream side of the metering valve and the injection pump.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of a liquid fuel pump in accordance with the invention,

FIGURE 2 is a section on the line 22 of FIGURE 1,

FIGURE 3 is a section on the line 33 of FIGURE 1,

FIGURE 4 is a diagrammatic view show-ingthe pump mounted on an engine and FIGURE 5 is a sectional scrap view showing a modification of part of the pump shown in FIGURE 1.

In the example shown there is provided a body part in which is mounted a rotary distributor member 11 which is adapted to be driven in timed relationship with an engine 12 with which the pump is associated. Formed in the distributor is a transverse bore 13 in which are mounted a pair of reciprocable plungers 14. Moreover, the plungers are arranged to be moved inwardly as the distributor rotates, by a plurality of cam lobes 15 formed on the internal periphery of a ring 16 secured in the body part, there being provided intermediate the plungers 14 and the cam lobes, rollers 17 respectively which are supported in carriers 18 slidable in the distributor.

At the other end of the distributor is mounted a vane type feed pump 18 which draws liquid fuel from an inlet 19 mounted on the body part and which supplies fuel to a feed passage 20 formed in the body part. Moreover, a spring loaded relief valve 21 is provided to control the pressure of fuel delivered by the feed pump. This valve serves to control the output pressure of the feed pump so that it increases progressively with increase of the speed at which the distributor is driven by the engine. Within the distributor is formed a longitudinal passage 22 which at one end is in communication with the transverse bore 13 and which at another point is in communication with a plurality of equi-angularly spaced radially extending inlet passages 23 equal in number to the number of cylinders of the engine with which the pump is associated.

At another point the longitudinal passage 22 communicates with a radially extending delivery passage 24 and this is arranged to register, in turn, as the distributor rotates with a plurality of equi-angularly spaced delivery ports 25. The delivery ports communicate respectively with injection nozzles 26a mounted on the engine in a position to direct fuel into thecombustion spaces of the engine respectively. Furthermore, the communication of the delivery passage 24 with a delivery port 25 is arranged to take place whilst the plungers 17 are being moved inwardly by the cam lobes 15.

In the body part is formed a stepped cylinder 26 having its inner and narrower end in communication with an inlet port 27. Furthermore against a step in the cylinder is located a plate 28 having an aperture formed therein having a smaller diameter than the diameter of the narrower end of the cylinder. Slidably mounted within the narrower end of the cylinder and the aperture in the plate 28 is a stepped shuttle 29, the maximum -permitted outward movement of which is limited by an adjustable stop 30 which also serves to close the wider end of the cylinder. The wider end of the cylinder communicates with the aforesaid supply passage 20 and the space defined between the shuttle 29 and the plate 28 communicates with the space in which the rollers 17 move. This space is vented to the inlet 19 through passages not shown. The inlet port 27 is positioned so as to communicate with the inlet passages 23 in turn, as the distributor rotates and this communication is arranged to take place during part of the time when the delivery passage 24 is out of register with a delivery port.

Also provided in the body part is a cylindrical bore 31 in which is mounted an axially movable throttle member 32. The throttle member is loaded towards the inner end of its bore by a coiled compression spring 33 which is mounted intermediate the throttle member and an adjustable abutment 34 the setting of Which can be adjusted by an operator controlled lever 35 pivotally mounted on the body part. The inner 'end of the bore 31 is in communication w-ith the supply passage 20 by way of an annular groove formed in the distributor. In the wall of the bore is formed a metering port 36 and this communicates with a circumferential groove 37 formed in the distributor. From the groove 37 extend a plurality of longitudinal grooves 38 equal in number to the number of inlet passages 23 and arranged alternately therewith. The grooves are arranged to register with the aforesaid inlet port 27 at least during part-of the time when the delivery passage is out of register with a delivery port. Furthermore, in the periphery of the metering valve there is formed a circumferential groove which communicates with the inner end of the bore 31 by way of a passage formed in the metering valve.

The operation of the pump will be described starting from the position in which the distributor is shown in the drawings. In this position the transverse bore 13 contains a metered volume of liquid fuel and as the distributor rotates the delivery passage 24 is brought into communication with one of the delivery ports and at the same time the plungers 14 are moved inwardly by the cam lobes thereby displacing fuel from the transverse bore to the appropriate injection nozzle 26a. At substantially the same time one of the longitudinal grooves 38 registers with the inlet port 27 and fuel flows from the feed pump 18 to the inner end of .the cylinder 26, thereby causing the shuttle to be moved outwardly. This outward movement of the shuttle is allowed owing to the fact that the fuel from the feed pump delivered to the inner end of the cylinder acts over a larger area of the shuttle than the fuel pressure which is applied to the outer end of the shuttle. Moreover, the rate at which fuel passes into the inner end of the cylinder is controlled by the axial setting of the metering valve, which controls the eliective size of the port 36.

As the distributor further rotates the communication between the delivery passage and a delivery port is broken and the inlet port 27 is brought into communication with an inlet passage 23. When this occurs fuel from the inner end of the cylinder 26 is discharged into the bore 13 causing the plungers therein to be moved outwardly, where after the cycle as described is repeated and fuel is delivered to the combustion spaces of the engine in turn. As previously mentioned the maximum outward movement is limited by an adjustable stop so that the maximum quantity of fuel which can be fed to the engine is closely controlled. The metering valve 32 moreover acts as an hydraulic governor to control the rate at which fuel is delivered to the engine in accordance with the speed of the latter. This is because as the speed of the engine increases the metering valve is moved further against the action of the spring 33 thereby reducing the effective size of the port 36 for a given setting of the abutment 34. When it is desired to increase the rate of supply of fuel to the engine the abutment 34 is moved to increase the force exerted by the spring 33 on the metering valve.

If desired the shuttle 29 can be formed in two parts 29a and 29b, as shown in FIGURE 5, and in this manner the risk of the shuttle sticking due to the aperture in the plate 28 and the cylinder not being concentric is minimised. As shown in the drawings the shuttles 29 and 29a are provided with conical ends which co-operate with a conical surface defined at the end of the cylinder 26 to limit the movement of the shuttle. It is important however to ensure that the included angle of the shuttle is greater than that of the cylinder so that fuel under pressure entering the cylinder can act on the whole of the end of the shuttle.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A pumping apparatus for supplying fuel to an internal combustion engine and comprising a body part, a distributor member rotatably mounted therein and arranged to be driven in timed relationship with the engine, a bore defined in the distributor member, a plunger mounted in the bore, a cam mounted in the body part for imparting inward movements to the plunger as the distributor is rotated, an outlet port formed in the body part, a delivery passage formed in the distributor and in communication with said bore, said delivery passage being arranged to register with the outlet port as the distributor member rotates and during the time when the plunger is being moved inwardly, an inlet port formed in the body part, an inlet passage formed in the distributor and in communication with said bore, said inlet passage being arranged to register with the inlet port during part of the time when the plunger is not being :moved inwardly by the cam, a cylinder defined in the body part, a stepped shuttle moveable in said cylinder, the wider end of the shuttle together with the wall of the cylinder defining a chamber which is in communication with said inlet port, conduit means through which the narrower end of the shuttle is exposed to the pressure of fuel delivered by a source of fuel under pressure, and passage means defined 'by the distributor, said passage means being arranged to register with the inlet port during part of the time when the inlet passage is not in register therewith, said passage means being in communication with said source of fuel, and throttle means for controlling the rate of which fuel can flow from said source through said passage means to said chamber, the arrangement being such that when fuel is fed to said chamber from said source the shuttle will be moved in one direction by an amount dependent upon the setting of said throttle means and when the inlet passage is in register with said inlet port the fuel pressure acting on the narrower end of the shuttle will move the shuttle so as to displace the fuel previously fed to the chamber to the bore so as to cause the plunger to be moved outwardly.

2. A pumping apparatus for supplying fuel to an internal combustion engine and comprising a body part, a distributor member rotatably mounted therein and arranged to be driven in timed relationship with the engine, a bore defined in the distributor member, a plunger. mounted in the bore, a cam mounted in the body part for imparting inward movements to the plunger as the distributor is rotated, an outlet port formed in the body part, a delivery passage formed in the distributor member and in communication with said bore, said delivery passage being arranged to register with the outlet port as the distributor member rotates and during the time when the plunger is being moved inwardly, an inlet port formed in the body part, an inlet passage formed in the distributor and in communication with said bore, said inlet passage being arranged to register with the inlet port during part of the time when the plunger isnot being moved inwardly by the cam, a feed pump driven by the distributor member,

and having an inlet and an outlet, the inlet being arranged in use to be connected to a source of fuel, a cylinder defined in the body part, a stepped shuttle moveable in the cylinder, the wider end of the shuttle together with the wall of the cylinder defining a chamber which is in communication with said inlet port, conduit means through which the narrower end of the shuttle is exposed to the pressure of fuel delivered by said feed pump, and passage means defined by the distributor said passage means being arranged to register with the inlet port during part of the time when the inlet passage is not in register therewith,

said passage means being in communication with the outlet of-said feed pump, throttle means for controlling the rate at which fuel can flow from the said feed pump through said passage means to said chamber, and adjustable stop means for limiting the movement of the shuttle, the arrangement being such that when fuel is fed to said chamber from said feed pump the shuttle will be moved in one direction by an amount dependent upon the setting of said throttle means and when the inlet passage is in register with said inlet port the fuel pressure acting on the narrower end of the shuttle will move the shuttle so as to displace the fuel previously fed to the chamber to the bore so as to cause the plunger to be outwardly.

3. Apparatus as set forth in claim 2 in which the cylinder is of stepped form, the narrower end of the cylinder being complementary to the wider end of the shuttle, a plate located in the wider end of the cylinder, an aperture formed in said plate through which the narrower end of the shuttle extends, and passage means for venting the portion of the narrower end of the cylinder adjacent the plate.

4. Apparatus as set forth in claim 3 in which the shuttle is formed of two parts complementary in size to the narrower end of the cylinder and the aperture respectively.

References Cited by the Examiner UNITED STATES PATENTS 3,025,797 3/1962 Hut-cheon 1032.1 3,058,425 10/1962 Evans 1032.1 3,101,079 8/1963 Evans l032.l 3,168,042 2/1965 Bessiere 1O3----2.1

MARK NEWMAN, Primary Examiner.

\V. J. KRAUSS, Assistant Exqminer, 

1. A PUMPING APPARATUS FOR SUPPLYING FUEL TO AN INTERNAL COMBUATION ENGINE AND COMPRISING A BODY PART, A DISTRIBUTOR MEMBER ROTATABLY MOUNTED THEREIN AND ARRANGED TO BE DRIVEN IN TIMED RELATIONSHIP WITH THE ENGINE, A BORE DEFINED IN THE DISTRIBUTOR MEMBER, A PLUNGER MOUNTED IN THE BORE, A CAM MOUNTED IN THE BODY PART FOR IMPARTING INWARD MOVEMENTS TO THE PLUNGER AS THE DISTRIBUTOR IS ROTATED, AN OUTLET PORT FORMED IN THE BODY PART, A DELIVERY PASSAGE FORMED IN THE DISTRIBUTOR AN DIN COMMUNICATION WITH SAID BORE, SAID DELIVERY PASSAGE BEING ARRANGED TO REGISTER WITH THE OUTLET PORT AS THE DISTRIBUTOR MEMBER ROTATES AND DURING THE TIME WHEN THE PLUNGER IS BEING MOVED INWARDLY, AN INLET PORT FORMED IN THE BODY PART, AN INLET PASSAGE FORMED IN THE DISTRIBUTOR AND IN COMMUNICATION WITH SAID BORE, SAID INLET PASSAGE BEING ARRANGED TO REGISTER WITH THE INLET PORT DURING PART OF THE TIME WHEN THE PLUNGER IS NOT BEING MOVED INWARDLY BY THE CAM, A CYLINDER DEFINED IN THE BODY PART, A STEPPED SHUTTLE MOVEABLE IN SAID CYLINDER, THE WIDER END OF THE SHUTTLE TOGETHER WITH THE WALL OF THE CYLINDER DEFINING A CHAMBER WHICH IS IN COMMUNICATION WITH SAID INLET PORT, CONDUIT MEANS THROUGH WHICH THE NARROWER END OF THE SHUTTLE IS EXPOSED TO THE PRESSURE OF FUEL DELIVERED BY A SOURCE OF FUEL UNDER PRESSURE, AND PASSAGE MEANS DEFINED BY THE DISTRIBUTOR, SAID PASSAGE MEANS BEING ARRANGED TO REGISTER WITH THE INLET PORT DURING PART OF THE TIME WHEN THE INLET PASSAGE IS NOT IN REGISTER THEREWITH, SAID PASSAGE MEANS BEING IN COMMUNICATION WITH SAID SOURCE OF FUEL, AND THROTTLE MEANS FOR CONTROLLING THE RATE OF WHICH FUEL CAN FLOW FROM SAID SOURCE THROUGH SAID PASSAGE MEANS TO SAID CHAMBER, THE ARRANGEMENT BEING SUCH THAT WHEN FUEL IS FED TO SAID CHAMBER FROM SAID SOURCE THE SHUTTLE WILL BE MOVED IN ONE DIRECTION BY AN AMOUNT DEPENDENT UPON THE SETTING OF SAID THROTTLE MEANS AND WHEN THE INLET PASSAGE IS IN REGISTER WITH SAID INLET PORT THE FUEL PRESSURE ACTING ON THE NARROWER END OF THE SHUTTLE WILL MOVE THE SHUTTLE SO AS TO DISPLACE THE FUEL PREVIOUSLY FED TO THE CHAMBER TO THE BORE SO AS TO CAUSE THE PLUNGER TO BE MOVED OUTWARDLY. 